One type of packaging machine that is commonly used in the food industry is known as a Vertical Form Fill Sealing (VFFS) machine. This type of machine constructs bags from a continuous roll of plastic film, fills the bags with their contents (which can either be solid, powder or liquid), and seals the bags once filled.
Typically, the roll of film is pre-printed with labeling on its exterior surface and sell by dates and production codes are printed on the film as the bags are passed through the machine. The film is passed through a series of rollers and fed towards a hollow conical feeder tube oriented vertically. As the centre of the film approaches the tube, the outer edges of the film are wrapped around the tube by so-called forming shoulders. A vertical seal is then applied to the overlapping edges of the film by a heated bar. A horizontal seal is then applied by another heated bar across the bottom edge of the tube of film. The contents of the bag are then dispensed through the feeder tube into the bag and the horizontal heated bar is then re-applied to simultaneously seal the top of the bag and the bottom of the next bag above. The filled bag is then cut from the tube ready for boxing and shipping as a sealed unit.
In some applications, a so-called “Euro-slot” or hanging aperture is provided for suspending the bags on display rails in retail outlets. The hanging aperture is punched or cut through the top of the bag just prior to the final sealing of the bag, when the bags are manufactured on their side. However, the throughput of the machine is hampered by the need to slow or stop the machine while the hanging apertures are being punched or cut. Consequently, production rates and manufacturing costs are adversely affected.
It is therefore an aim of the present invention to provide an improved packaging method and apparatus.